1. Field of the Invention
The invention relates to a disposable sensor head for an optical sensor, comprising a central body having an axial through-channel closed by a transparent viewing disk oriented transversely with respect to its longitudinal direction, and a circumferential fastening flange, by means of which the central body is fastenable in a sealing fashion on a wall of a flexible container in such a way that the through-channel passes through the wall. The invention furthermore relates to a disposable container having a flexible wall and at least one disposable sensor head of an optical sensor, wherein the sensor head comprises a central body having an axial through-channel closed by a transparent viewing disk oriented transversely with respect to its longitudinal direction, and a circumferential fastening flange and by means of the fastening flange the central body is fastened in a sealing fashion on the flexible wall in such a way that the through-channel passes through the wall.
2. Description of the Related Art
Disposable sensor heads and disposable containers are known from 10 2006 001 610 B4.
Particularly in the pharmaceutical and biotechnological industries, for the production, storage and use of liquids and gases (referred to together as fluids below), disposable containers having flexible walls are used instead of the previously more commonly used rigid tanks and cylinders. Such disposable containers will be referred to here as bags for brevity. As in the case of rigid containers, the monitoring of a very wide variety of parameters of the fluids in the bags is necessary. To this end, it is known from the aforementioned document to use optical sensors passing through the bag wall. For reasons of costs as well as sterilization, the sensor head, i.e. the part of the sensor forming the optical contact with the fluid to be monitored, is formed as a disposable element which is delivered to the customer firmly connected to the bag and sterile, and is disposed of together with the bag after use of the latter. In this case, it is desirable to accommodate reusable, expensive and/or non-sterilizable components, for example light sources, electronic evaluation units, etc. in a couplable module, and as far as possible to accommodate only robust, inexpensive, sterilizable and easily disposable elements in the disposable sensor head.
In one of the exemplary embodiments disclosed in DE 10 2006 001 610 B4, the central body firmly clamped to its fastening flange on the bag wall by means of a backing piece comprises a central through-bore. The latter forms a through-channel which has an inlet lying outside the bag and an outlet lying inside the bag, and therefore passes through the bag wall. A volume flow through the through-channel is prevented by a viewing disk, which seals the channel. The viewing disk is transparent, which in the scope of the present description is respectively to be understood in relation to the measurement to be carried out and means a sufficient transmissivity for light of the wavelengths required for the measurements in question. In the known embodiment, this viewing disk is applied on the outlet of the through-channel and closes the latter in the shape of a dome. It forms the optical interface between a fluid inside the bag and a glass fiber, which is arranged inside the channel and inputs illumination light and outputs detection light.
Such a sensor head is suitable for carrying out back-scattering, fluorescence and phosphorescence measurements. Transflection measurements, such as may be used particularly in the scope of NIR spectroscopy (near-infrared spectroscopy), cannot be carried out with the known sensor head.
It is an object of the present invention to further refine the known disposable sensor head, in such a way that transflection measurements, in particular NIR spectroscopy measurements, can be carried out with it.
It is another object of the present invention to provide sensor-equipped bags which permit transflection examination, in particular an NIR spectroscopy examination, of the bag contents.